Clean money: The new International Corruption Unit will help restore Britain's reputation as a positive global influence

For reasons that we are all perhaps wearily familiar with – relative economic decline, disastrous participation in illegal foreign wars, a Prime Minister too detached from the European Union to play a leading role, strained defence budgets – Britain is not the force it was in international affairs. This is most painfully apparent in the refugee crisis, where Downing Street is now struggling to catch up with public opinion, and in the recent Ukraine conflicts, where the UK was barely a bit-part player in the attempts led by Angela Merkel and François Hollande to avoid a fatal conflict with Russia.

So it is all the more welcome that this middle-ranking power has decided to set up the International Corruption Unit, part of the National Crime Agency, which will target some of the most corrupt figures across the world. Perhaps that is overambitious, but it is at least an attempt to take a British lead in the fight against one of the least talked about but most potent threats to global prosperity and peace: corruption.

It is, after all, one of the biggest reasons why sub-Saharan Africa has not emulated the economic growth of other emerging markets, and also the greatest factor in the failure of those markets to grow to their full potential; witness the well-publicised corruption cases in Brazil, involving people at the very top of government with oil giant Petrobas. Then there’s China, India and Russia, where corruption is, more or less, a way of life, abetted by state-controlled or merely quiescent media.

Corruption also plays an obvious part in the pernicious trade in people that has exploited so many desperate refugees. Bent officials, bribery and money laundering is behind much of the illegal trade in armaments, drugs, ivory and blood diamonds. It has led to companies, even large and mostly legitimate ones, evading taxation, thus starving public services of resources, and winning orders through paying bribes. Corruption has, in other words, caused incalculable human, environmental and economic damage, even though it is, to a large degree, invisible.

So the idea that the British are to take the lead in the pursuit of the corrupt at home and abroad is especially welcome, restoring as it does part of our international reputation in a practical fashion, as well as being a valuable goal in itself. Some 20 of the world’s most corrupt politicians involved in laundering millions of pounds through the City are to be investigated in a major expansion of our international anti-graft operations.

It represents the flip-side of Britain’s sometimes exaggerated prowess in financial services – for that same expertise can be used to ill-effect, and London has long been a favourite destination for money requiring dry cleaning. We have the clever lawyers, accountants and bankers to do the job; now we may also be able to match them in official attempts to curb such activity.

When the FBI raided Fifa and ended the old assumption that corruption in world football was just something everyone had to live with, it broke a spell. Carting off Fifa grandees showed that there is no reason why rich and powerful officials in any country cannot be pursued for their alleged wrongdoing.

Of course it will always be difficult to win the co-operation of the authorities in, say, Russia or Uzbekistan; but we can at least make the effort and we can prevent them from abusing the financial facilities of London and the rest of the Western world. The modest £21m made available to the new unit is money that will be used to good effect; we cannot say the same for the thousand times more we have expended on the wars in Afghanistan and Iraq.